Lithotripsy apparatus using a flexible endoscope

ABSTRACT

An apparatus and method are presented comprising an endoscope including a flexible shaft which has an active deflection section at a distal tip, a handle connected to a proximal end of the flexible shaft, a platform mounted to a top portion of the handle and oriented substantially in line with the longitudinal axis of the proximal end of a straight portion of the flexible shaft to provide a substantially straight entry into a working channel of the flexible shaft for an output accessory, a stone retrieval device insertable into the proximal end of the working channel of the endoscope, a lithotripsy shaft including one or more guide features at a distal end of the lithotripsy shaft to facilitate passage of wires or filaments of the stone retrieval device there through, and a lithotripsy shaft driver attached to the platform for driving the lithotripsy shaft under power.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. Non-Provisionalapplication Ser. No. 15/788,027, filed Oct. 19, 2017, now issued as U.S.Pat. No. 10,478,205, which is a Continuation of U.S. Non-Provisionalapplication Ser. No. 14/864,937, filed Sep. 25, 2015, now issued as U.S.Pat. No. 9,820,763, which is a Continuation of U.S. Non-Provisionalapplication Ser. No. 13/815,626, filed Mar. 13, 2013, now issued as U.S.Pat. No. 9,168,099, which claims priority to U.S. Provisionalapplication No. 61/795,809, filed Oct. 25, 2012, the contents of each ofthe above identified applications are herein incorporated by referencein their entirety.

FIELD OF THE INVENTION

The present invention relates to an apparatus and method for breakingphysiologic calculi or “stones” using lithrotripsy, more particularly toan apparatus and method for breaking stones using a flexible endoscopewith a steerable tip and an elongate rigid lithotripsy shaft incombination with a stone retrieval device extending therethrough.

BACKGROUND

Medical endoscopes were first developed in the early 1800 s and havebeen used to inspect inside the body. A typical endoscope consists of adistal end comprising an optical or electronic imaging system and aproximal end with controls for manipulating the tools and devices forviewing the image, with a solid or tubular elongate shaft connecting theends. Some endoscopes allow a physician to pass tools or treatments downa hollow channel, for example, to resect tissue or retrieve objects.

Over the past several decades, several advances have been made in thefield of endoscopy, and in particular relating to the breaking up ofphysiologic calculi in the bile ducts, urinary tracts, kidneys, and gallbladder. Physiological calculi in these regions may block ducts andcause a patient a substantial amount of pain and therefore must bebroken down and/or removed. Different techniques have been developed tobreak up stones, including ultrasonic lithotripsy, pneumaticlithotripsy, electro-hydraulic lithotripsy (EHL), and dissolution ofcalculi using green light, YAG, or holmium lasers.

A number of rigid solid or tubular shaft-based lithotripsy devices thatuse ultrasonic or pneumatic energy to break the stone into smallerpieces for easier removal from the patient's urologic system have beendeveloped. For example, the Olympus LUS-2, the Gyrus ACMI Cyberwand, andthe Swiss Lithoclast are such devices. Ultrasonic or acoustic frequencyenergy is transmitted down a stiff metal shaft and delivered by contactto a kidney stone. Ultrasonic lithotripters require tuned shafts and theeffectiveness of these lithotripters depend on their ability to maintainresonance down the length of the shaft (i.e. ultrasonic energy does nottravel well around bends or turns). Probe bending can dissipate enoughheat to seriously damage adjacent tissue, in addition to the loss ofenergy transfer at the tip of the probe.

For procedures performed with a tubular shaft device, suction of liquidand debris during the lithotripsy procedure is possible via the centerof the tubular shaft. Some devices incorporate and deliver a lowerfrequency energy component to the kidney stone either through the sameshaft or via a second shaft; this second shaft is usually coaxial to theultrasonic energy shaft (i.e. the Cyberwand). This secondary, lowerfrequency shows evidence of improving the stone breaking efficiency overa solely ultrasonic energy approach.

The use of such a lithotripsy device requires that the stone beingbroken is pressed up against some surface, usually an inner wall of thekidney, in order that the vibrational energy can be sufficientlydelivered to the stone surface to break it up. Some devices now on themarket offer a combination of a lithotripsy shaft and a stone basket(i.e. the Swiss Lithobasket) where the lithotripsy shaft is incorporatedinto the center of the lithotripsy basket shaft and emerges into thecenter of the lithotripsy basket. The Swiss Lithobasket allows for theability to apply the Swiss Lithoclast pneumatically driven shaft to akidney stone contained in the associated basket, however this device islimited in that no suction is possible through the lithotripsy shaft.

Laser lithotripsy involves the use of laser fibers to effectively breakup stones in virtually any area of the urinary system. When used withflexible ureteroscopes, laser fibers can bend around corners and accesskidney stones in the lower pole of the kidney. A problem with thisapproach is that laser fibers have been known to break inside theworking channel and damage flexible ureteroscopes. Some techniques havebeen developed for laser lithotripsy using semi-rigid ureteroscopes tomake stones accessible by a straighter path. However, laser lithotripsyin general has a much more expensive start-up cost vs, ultrasoniclithotripsy due to the relative capital equipment costs.

The size, stiffness and length of the straight shafts in much of theexisting ultrasonic lithotripter technology only allow for the use ofsuch lithotripters with large shafts in percutaneous procedures, i.e.direct access to stones in the kidney through a small incision in thepatient's back and on into the kidney itself. Percutaneous access tophysiological calculi with laser lithotripsy provides one solution toprevent breaking and damage of flexible endoscopes during laser orultrasonic lithotripsy. However, this approach requires more intensiveanesthesia and can have longer recovery times for the patient.

Electrohydraulic Lithotripsy (EHL) provides a similar ease of access viaa flexible endoscope as laser lithotripsy with generally lower cost, butwith also generally lower stone fragmentation efficiency as well as someconcerns about local shockwave effects on nearby tissue.

Additionally, a predominant majority of current lithotripsy shafts aredistally terminated smoothly and perpendicular to the shaft axis. Thissmooth, flat surface, while providing more protection to soft tissuebecause of the inherent smoothness, can make it extremely easy for theactivated shaft to slip off a stone, or for a stone to slide out frombeneath the vibrating smooth tip and thus prolong the stone breakingprocedure as the physician “chases” the stone around.

Despite the approaches discussed above, there is still a need for anendoscoope device that allows for reliable functionality and easy accessof a lithotripsy device or shaft to physiologic calculi with a rigid,semi-rigid or semi-flexible shaft of an endoscope without the need toapproach the physiologic calculi percutaneously, by providing asubstantially straight or minimally curved entry channel for a rigid,semi-rigid or semi-flexible lithotripsy shaft from an entry port todistal tip of an endoscope. In addition, there is a need for alithotripsy shaft with guide features to facilitate passage of a stoneretrieval device there through such that the stone retrieval device isable to retrieve a stone and place it in line with the substantiallystraight shaft lithotripter.

SUMMARY OF THE INVENTION

The present invention meets one or more of the above needs by providingan endoscope with a mounting platform oriented substantially in linewith the longitudinal axis of a straight portion of a flexible shaftwhich provides a straight entry into a working channel of a flexibleshaft in a combined lithotripsy and stone retrieval system. One or moreguide features at the distal tip of a lithotripsy shaft provide easyentry for a stone retrieval device into the lithotripsy shaft. Further,the tip of the lithotripsy shaft may be provided with contouringfeatures including tapering or beveling to further assist in a smoothentry of the wires of the stone retrieval device into the lithotripsyshaft. Further still, the tip of the lithotripsy shaft may be sharp,pointed, or otherwise piercing in order to maintain contact with a stoneduring active destruction of physiologic calculi and to aid inadvantageous fragmentation of a stone.

Physiologic calculi of interest for these purposes can be foundtypically in the bile ducts, urinary tract, kidneys, bladder, and gallbladder. Endoscopes to access these stones are referred to ascholedochoscopes, ureteroscopes, nephroscopes, cystoscopes, andduodenoscopes respectively. It is contemplated that the details of thepresent invention may be applied to any type of endoscope.

As an example, in the case of ureteral endoscope access into a kidney,the device of the present invention is capable of retrieving stones inthe lower pole or one of the lower calyxes of the kidney and moving theminto the upper pole or into the ureteropelvic junction (UPJ) in theurinary system which would provide an access geometry to the capturedstone that was a straight or substantially straight line to the kidneyusing a deflectable distal end of an endoscope tip and then, with thekidney stones more accessible via a substantially straight or minimallycurved line path, engage in lithotripsy activities using semi-rigid,rigid or semi-flexible lithotripsy shafts which are known to be moredurable than substantially flexible shaft distal tips. Accordingly, itis contemplated that the apparatus of the present invention would becapable of retrieving and relocating physiologic calculi in any hard toreach position within a patient's anatomy.

In one exemplary embodiment, a stone basket or stone grasper extendedfrom the distal tip of a flexible shaft can access a stone in atraditionally difficult-to-reach location. It is contemplated that thiscould be accomplished by changing the orientation of a flexible distalend of an endoscope while actively visualizing the anatomy and stoneposition to retrieve a stone that would be hard to effectively break, inthe original position in which it was located. The stone may besubsequently pulled into a position which is more easily accessed with astraight, semi-rigid or semi-flexible shaft lithotripter (i.e. at theend of the substantially straight or minimally curved shaft of theendoscope, with the deflection portion of the flexible shaftstraightened into a substantially straight or minimally curved lineorientation). To accomplish this, the stone retrieval device exits thedistal end of the endoscope shall through a tip of a straight shaftlithotripsy probe, where the lithotripsy probe may be in a retractedposition behind a substantially deflectable portion of a flexible shaftendoscope, and which may be provided with a wire guide, and then thestone retrieval device is used to grasp and relocate a stone originallyfound not in a substantially straight-line location for ureteral access,to such a substantially straight-line location, for example,Subsequently, the stone retrieval device (i.e. stone basket or stonegrasper or other equivalent) may be withdrawn into the endoscope shaftand into the straight lithotripsy shaft. The lithotripsy shaft, whichmay be driven pneumatically, ultrasonically, mechanically,electromechanically, electromagnetically, or by a combination ofdifferent driving power, can then be advanced to crush the stone whenthe target stone is placed in front of the lithotripsy shaft distal tip.Remaining stone fragments can be retrieved with the stone basket orstone grasper and placed in line with the endoscope shaft to be furtherbroken down.

Accordingly, pursuant to one aspect of the present invention, there iscontemplated an apparatus, an endoscope including a flexible shaft whichhas an active deflection section at a distal tip; a handle connected toa proximal end of the flexible shaft oriented at an angle with respectto the longitudinal axis of the proximal end of a straight portion ofthe flexible shaft; and a platform mechanism mounted to a top portion ofthe handle and oriented substantially in line with the longitudinal axisof the proximal end of a straight portion of the flexible shaft toprovide a straight entry into a working channel of the flexible shaftfor an output accessory.

The invention may be further characterized by one or any combination ofthe features described herein, such as an endoscopic tool is insertableinto a proximal end of the working channel for breaking up a stone atthe distal end of the flexible shaft of the endoscope by protrudingtherefrom and passing energy to the stone; the endoscopic tool is alithotripsy shaft and is insertable into a proximal end of the workingchannel for breaking up a stone at the distal end of the flexible shaftof the endoscope by protruding therefrom and impacting the stone withforce; the endoscopic tool is a laser fiber and is insertable into aproximal end of the working channel for breaking up a stone at thedistal end of the flexible shaft of the endoscope by protrudingtherefrom and imparting laser light onto the stone; a stone retrievaldevice is insertable into the proximal end of the working channel of theendoscope for retrieval of a stone at a distal end of the flexible shaftof the endoscope by protruding therefrom; the lithotripsy shaft isprovided with one or more guide features at a distal end of thelithotripsy shaft to facilitate passage of wires or filaments of a stoneretrieval device therethrough; the stone retrieval device is a stonebasket or a stone grasper; the endoscope is provided with controls forcontrolling movement of any one or more of deflection of the activedeflection section of the flexible shaft extension and retraction of thestone retrieval device, the extension and retraction of the endoscopictool from the distal end of the endoscope, or active stone breaking viadriving of the lithotripsy shaft.

Pursuant to another aspect of the present invention, there iscontemplated an apparatus, an endoscope including a flexible shaft whichhas an active deflection section at a distal tip; a handle connected toa proximal end of the flexible shaft oriented at an angle with respectto the longitudinal axis of the proximal end of a straight portion ofthe flexible shaft; a platform mounted to a top portion of the handleand oriented substantially in line with the longitudinal axis of theproximal end of a straight portion of the flexible shaft to provide asubstantially straight entry into a working channel of the flexibleshaft for an output accessory; a stone retrieval device insertable intothe proximal end of the working channel of the endoscope for retrievalof a stone at a distal end of the flexible shaft of the endoscope byprotruding therefrom; a lithotripsy shaft including one or more guidefeatures at a distal end of the lithotripsy shaft to facilitate passageof wires or filaments of the stone retrieval device there through; and alithotripsy shaft driver attached to the platform for driving thelithotripsy shaft under power.

The invention may be further characterized by one or any combination ofthe features described herein, such the stone retrieval device is astone basket or a stone grasper; the endoscope is provided with controlsfor controlling movement of any one or more of deflection of the activedeflection section of the flexible shaft, extension and retraction ofthe stone retrieval device, the extension and retraction of thelithotripsy shaft from the distal end of the endoscope, or active stonebreaking via driving of the lithotripsy shaft.

Pursuant to yet another aspect of the present invention, there iscontemplated a method, comprising manipulating a deflection section at adistal tip of an endoscope toward a stone within the body; inserting alithotripsy shaft and a stone retrieval device into a proximal end of aworking channel of the endoscope; extending the stone retrieval devicefrom a distal tip of the deflection section through a lithotripsy shaft;capturing a stone with the stone retrieval device and bringing itsubstantially in line with the longitudinal axis of a substantiallystraight or slightly curved portion of a flexible shaft; withdrawing thestone retrieval device within the substantially straight or slightlycurved shaft of the lithotripsy shaft through one or more guide featuresat a distal tip of the lithotripsy shaft; extending the lithotripsyshaft toward the stone; and driving the lithotripsy shaft under powertoward the stone to break it up with force.

The invention may be further characterized by one or any combination ofthe features described herein, such as the stone retrieval device is astone basket or stone grasper; the lithotripsy shaft may be providedwith a sharp or textured tip; and the lithotripsy shaft may be drivenpneumatically, ultrasonically, mechanically, electromechanically,electromagnetically, or by a combination of different driving power.

Pursuant to yet another aspect of the present invention, there iscontemplated a method, comprising manipulating a deflection section at adistal tip of an endoscope toward a stone within the body; inserting astone retrieval device into a proximal end of a working channel of theendoscope; extending the stone retrieval device from a distal tip of thedeflection section; capturing a stone with the stone retrieval deviceand bringing it substantially in line with the longitudinal axis of asubstantially straight or slightly curved portion of a flexible shaft;withdrawing the stone retrieval device from the endoscope; extending alaser fiber through the working channel and toward the stone to break upthe stone using laser light.

Further aspects, advantages and areas of applicability will becomeapparent from the description provided herein. It should be understoodthat the description and specific examples are intended for purposes ofillustration only and are not intended to limit the scope of the presentdisclosure.

DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a cross-sectional profile view of an illustrative example ofan endoscope in accordance with the teachings of the present invention.

FIG. 2 is an exploded view of a lithotripsy shaft tip with guidefeatures in accordance with one embodiment of the present invention.

FIG. 3 is an exploded view of a lithotripsy shaft tip with guidefeatures in accordance with another embodiment of the present invention.

FIG. 4 is a cross-sectional profile view of an illustrative example of alithotripsy shaft tip with guide features and a stone retrieval devicein accordance with the teachings of the present invention.

FIG. 5 is an exploded view of the distal end of the lithotripsy shaftwith stone retrieval device extending therethrough in accordance withthe teachings of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

As will be seen, the devices and methods taught herein offer convenientaccess with a flexible endoscope to stones in the body. The presentinvention describes an improved lithotripsy system which is comprised ofa flexible endoscope, an impact shaft lithotripter, and a stoneretrieval device, which allows for more efficient access to, as well asacquisition and fragmentation of, physiologic calculi.

One embodiment of the invention may use a tubular impact-transmittinglithotripsy shaft provided with guide features at the tip for better,more consistent engagement with a stone for better fragmentationefficiency. Such guide features could also be designed to have bettercompatibility with stone retrieval device design so as to protect theelements of a stone retrieval device and facilitate the ability of thestone retrieval device to bring a stone to the distal tip of thelithotripsy shaft. Such a lithotripsy shaft may have a substantiallystiff characteristic, capable of providing column strength and rigidity,in order to transmit impact energy from its driver to its distal tip andthus may have limited flexing or bending capability while retaining suchimpact energy transmission capabilities. It is contemplated that such alithotripsy shaft would preferably be provided access to a stone needingfragmentation via a straight line path, substantially close to astraight line, or a minimally curved path. The angle with which thelithotripsy driver may deviate from the lithotripsy shaft is describedas angle α The straighter the access from the lithotripsy driver to thelithotripsy shaft, the better suited the device as a whole will be toutilize energies which are more effectively transmitted via a straightshaft, including ultrasonic energy. Furthermore, the angle of deflectionthat the lithotripsy shaft may deviate from a straight line out fromits' exit from the lithotripsy driver to a stone needing fragmentationand this deflection angle may be described as β. The ability toeffectively fragment a stone via a slightly curved shaft is highlydesirable as the anatomy encountered may not support an entirelystraight access to a stone.

The driver for the lithotripsy shaft may be connected to and/orsupported by, or integrated into the design of the endoscope in order toprovide a more “hands free” configuration. The driver for thelithotripsy shaft could be connected to the flexible endoscope in such away that it is mounted on a sliding translation stage or mechanism whichwould facilitate a more automatic positioning of the lithotripsy shaftrelative to the deflection section of the flexible endoscope. When movedto the proximal/rear end of the sliding mechanism, the driver and thelithotripsy shaft would be pulled back to a position where thelithotripsy shaft was removed from the deflection section of theflexible endoscope in such a way that the deflection section of theflexible endoscope would be able to perform its full deflection functionwithout interference from the lithotripsy shaft. When moved to thedistal/forward end of the sliding mechanism, the driver and thelithotripsy shaft would, through a substantially straight or minimallycurved flexible endoscope shaft, be moved forward through the workingchannel and the distal tip of the lithotripsy shaft would exit theworking channel and ideally be positioned at an optimum distance fromthe front of the flexible endoscope tip for visualization and stonefragmentation activity. Furthermore, it may be advantageous to have auser-controlled moving lever positioned for easy activation that, whenactivated, would provide to the user an ability to move the distal tipof the lithotripsy shaft distally and proximally a small distance andthus have better control over how the lithotripsy shaft engages thestone, perhaps eliminating the need to move the entire endoscopeforwards and backwards within the anatomy of interest. Such atranslation mechanism could be utilized to support a holder for otherworking channel tools, such as a laser fiber, which may also benefitfrom such translation and fine position control capabilities whileproviding the user with additional ease of use.

By way of example, when beginning a procedure such as kidney stoneremoval, one could have a combined assembly that included a flexibleendoscope, an attached lithotripsy driver with lithotripsy shaft locatedin the flexible endoscope working channel, and a stone basket deviceinserted into this overall assembly and ready for easy deployment tocapture a stone for ultimate removal from the urinary system. The stonelithotripsy driver and shaft would be positioned at a retracted positionso that the deflection section of the flexible endoscope would notexperience limitations in movement range due to interference from thelithotripsy shaft.

It is contemplated that different output accessories can be used withthe device of the present invention. In one embodiment, a lithotripsyshaft may be used in combination with a stone retrieval device (i.e.stone basket or stone grasper). Another embodiment might include a laserfiber used in combination with a stone retrieval device. Various otheralternatives and configurations are possible to remove a calculus ofinterest and are herein incorporated by reference.

It is contemplated that at a point where the flexible endoscope isstraightened out, the distal tip of the lithotripsy shaft could beadvanced forward and out of the distal tip of the flexible endoscopesuch that it could come in direct contact with the stone to befragmented. This could be accomplished either after the stone isreleased from the stone retrieval device with the stone retrieval deviceretracted into the endoscope and the stone in an advantageous positionfor the purposes of fragmentation or with the stone contained in thestone retrieval device and drawn toward the lithotripsy shaft tip by aretraction of the stone retrieval device. Subsequently, the lithotripsyshaft driver may be activated and the kidney stone of interestfragmented. If further stones needed to be fragmented and they were notaccessible via a straight path, the lithotripsy shaft could be retractedand the next stone of interest could be accessed, captured, andfragmented in the same way.

With the stones and fragments positioned closer to the exit of thekidney, and the stone basket accessible as part of the overall assembly,the stones or fragments could be captured by the stone retrieval deviceand withdrawn from the patient, with probably less internal damage tothe kidney and ureter as most of the extraction activities would bealong a substantially straight line. It is contemplated that the ideasof the present invention would result in less bumping and rubbingagainst the internal surfaces of the kidney and ureter and less tissueand blood debris generated and thus less compromise of visualizationduring the course of a procedure.

In one embodiment of the invention, the lithotripsy shaft can be appliedto a stone by itself, especially to reduce the size of a larger stone.Subsequently, a stone retrieval device can be deployed through theworking channel after the lithotripsy shaft has been removed to acquireand hold a smaller stone or stone fragment for further lithotripsy. Itis contemplated that irrigation or evacuation may be applied through thelithotripsy shaft as a tubular center core would allow for sufficientaccess, in particular for the case where there is no stone basket shaftpresent within the lithotripsy shaft.

In another embodiment of the invention, a friction adjustment may beprovided to set a drag friction in order to prevent the stone retrievaldevice wires from becoming overstressed and breaking. The frictionadjustment setting may be modified for different stone retrieval devicewire thicknesses and arrangements. Such a friction adjustment would helpto ensure that the stone retrieval device wires were not coming intoexcessive frictional contact with the edges of the lithotripsy shaft andbreaking during stone destruction or retrieval. Once the tension in thewires reached the desired limit, the tension on the stone retrievaldevice would be released or reduced, reducing the friction of thatdevice with the tip of the lithotripsy shaft to prevent breaking of thestone retrieval device wires or filaments.

Turning now to the drawings to illustrate examples of embodiments of thepresent teachings, FIG. 1 details the lithotripsy system using aflexible endoscope of the present invention. Endoscope 30 is providedwith flexible shaft 27, mount 28, lithotripsy shaft 12, stone retrievaldevice 14, translation stage 18, lithotripsy driver 17, as well ascontrol elements 18, 19, 20, and 23,

Flexible Shaft

Functionally, flexible shaft 27 is capable of active deflection at adistal tip 13 in order to reach around corners and bring stones tolocations that allow for improved straight line access such thatlithotripsy activities will be more effective.

Flexible shaft 27 enters the body in an extended position 11 a, and oncewithin the anatomy of interest can manipulate and deflect to deflectedposition 11 b using control wires. Control wires may be activated andmanipulated using deflection control lever 19. Deflection control levermay be capable of being locked in the center (i.e. in order to pulldifficult to reach stones into a position substantially in front of thestraight end of the distal tip 13 of endoscope 30).

Handle

Functionally, handle 29 may be connected to a proximal end of theflexible shaft via a strain relief 15 and may be oriented at an anglewith respect to the longitudinal axis of the straight portion offlexible shaft 27. Providing handle 29 at an off-axis angle allows forsubstantially improved straight line access through working channel 31for lithotripsy shaft 12 to impart maximum impact to physiologic calculiof interest at the distal end of the device.

One embodiment of the present invention provides lithotripsy driver 17in a straight line path with the straight portion of flexible shaft 27.Another embodiment provides lithotripsy driver 17 substantially in linewith the straight portion of flexible shaft 27 (i.e. lithotripsy driver17 may be oriented at an angle α with respect to the longitudinal axisof a straight portion of the flexible shaft). Angle α may range from0±15°, preferably from 0±5, and more preferably from 0±2°. Angle α maybe larger depending on shaft flexibility; however, the straighter theshaft that is provided, the better suited the device as a whole will beto utilize energies which are more effectively transmitted via astraight shaft, including ultrasonic energy.

Rigid, semi-rigid, or semi-flexible lithotripsy shafts 12 may enterthrough working channel 31 within handle 29 and effectively break upphysiologic calculi with these specifications. Strain relief 15 isprovided to protect the base of the shaft where it is attached to thescope from excessive bending at the proximal end of the shaft. The angleof deflection that the lithotripsy shaft may deviate from a straightline out from the lithotripsy driver to a stone needing fragmentation isdescribed as angle β. The ability to effectively fragment a stone evenvia a slightly curved shaft is highly desirable as the anatomyencountered may not support a totally straight access to a stone. Angleβ may range from 0±15°, preferably from 0±0.5° and more preferably from0±2°. Angle β may be larger depending on lithotripsy shaft flexibility;however, the straighter the lithotripsy shaft that is provided, thebetter suited the device as a whole will be to utilize energies whichare more effectively transmitted via a straight lithotripsy shaft,including ultrasonic energy.

Mounting Platform

A mounting platform 28 may be mounted to a top portion of handle 29 in agenerally perpendicular orientation with respect to handle 29 in orderto provide stability for lithotripsy driver 17 and translation stage 18at their connection to strain relief 15. The functionality of such aplatform or other mechanism for locating a lithotripsy or other kind ofdriver mechanism is to hold, align, and longitudinally translate alithotripsy driver or other useful mechanism substantially in-line withthe axis of the shaft of the endoscope may be realized by differentconfigurations than are presented herein. The platform may be taken tomean another mechanism for supporting a driver, for lithotripsy orotherwise, or a holding mechanism for supporting the passage of anelongate device down the working channel of the endoscope,

Stone Retrieval Device

Stone retrieval device 14, which may be a stone basket or stone grasper,may be insertable into the proximal end of endoscope 30 through workingchannel 31 for retrieval of a stone at a distal end of the flexibleshaft 27 of the endoscope by protruding therefrom. Stone retrievaldevice 14 may consist of any number of wires or filaments, but typicallywould have three, four, six, or eight wires, and may either be providedwith a tip or be tipless at a distal end.

Lithotripsy Shaft

Lithotripsy shaft 12 including one or more guide features at a distalend of the lithotripsy shaft to facilitate passage of wires or filamentsof the stone retrieval device there through. Guide features may include,as illustrated in FIGS. 2 and 3 beveling 32, tapering or funnel-shaping33, protrusions 34, guide passages 35, and/or sharp or pointed tips. Inthe illustrated embodiment, the distal tip of lithotripsy shaft 12 isprovided with either three or four protrusions. It is contemplated thatthese features may better protect the basket wires and guide their exitfrom the center of the hollow lithotripsy shaft. FIG. 4 illustrates aclose-up view of the stone retrieval device 14 extended through theguide features at the distal end of lithotripsy shaft 12.

Specific shaping of the lithotripsy shaft tip may encourage stonefragmentation by relatively sharp points or edges to more easily stayengaged with a stone and discourage movement away from the activatedtip, and perhaps a wedged design to more easily force separation of astone into disparate pieces and, by forcing the disparate piecesoutward, away from the central axis, reduce the potential of cloggingthe central passage of the lithotripsy shaft.

The advantage of having “points” or pronounced edges at the tip is thatthese would either “dig into” a kidney stone or at least align with anexisting rough texture on a harder stone and thus the stone and shaftwould be “interlocked” as the shaft was pushed against the stone andactivated. Stone breaking efficiency would be higher and thus procedureswould be shorter and more effective as the physician would spend lesstime “chasing” a stone around than they might with a smooth distal tipon the lithotripsy shaft.

The shape of the tip can also be designed to be compatible withdifferent designs of stone baskets, which can be inserted through thecore of the shaft and used to capture and hold a kidney stone forlithotripsy by the shaft Such designs as would be compatible with stonebaskets would be likely better described as crenellated as there wouldclearly be slots that the stone basket wires or elements would naturallyslip into and be more protected therein, i.e. not compressed between thestone material and the vibrating metal tip and therefore at risk to becut between the two.

Three-point distal tip 40 of lithotripsy shaft 12 may easily facilitatepassage of stone retrieval devices with either three or six wires (i.e.three-point symmetry). Four-point distal tip 41 of lithotripsy shaft 12may easily facilitate passage of stone retrieval devices with eitherfour or eight wires (i.e. four-point symmetry). Guide passages 35 ineither case provide easy passage of wires or filaments there through.Beveling and tapering further facilitate passage of stone retrievaldevice wires with minimal friction and/or abrasion. The above mentionedfeatures further minimize force and stress to the wires while the stonesare being broken up, and it is contemplated that such features wouldcontribute to longer stone retrieval device lifetimes.

In one embodiment of the invention, the lithotripsy shaft may be cut inspecial patterns along its length, such as with a laser, to make it moreflexible yet maintain the column strength necessary to deliversufficient ultrasonic or acoustic frequency or impact energy, forexample, to a kidney stone to break it up. Such shaft modificationswould make it easier to deliver the lithotripsy energy higher in theureter and into the upper ureteral junction or upper pole of the kidneywhen the lithotripsy shaft needed to bend slightly to accommodate andconform to constraints imposed by the anatomy.

The lithotripsy shaft may be fabricated in part, large or small, orentirely, of a closed coil spring, of round or flat wire or somevariation in between, to have more flexibility and ability intransmitting the stone breaking kinetic energy along a curved ornon-straight path. The lithotripsy shaft may be comprised of othermaterials, including shape memory alloys, including Nitinol and Tinel,titanium, stainless steel, or other materials known in the art. Theshape memory alloy material is used for its superelastic propertiesexhibited by the material's ability to deflect and resiliently return toits natural or predetermined position even when material strainsapproach 4%, or an order of magnitude greater than the typical yieldstrain of 0.4% giving rise to plastic deformation in common metals.Thus, the term “superelastic alloy” is used to denote this type ofmaterial. The distal tip of the lithotripsy shaft may be of a differentmaterial than that of the shaft, or have different treatment, such aslocalized hardening, than the rest of the shaft so as to be more durableagainst hard stone material. The distal tip may be smaller, or larger,in diameter than the lithotripsy shaft, in order to gain better accessto a stone, or have a better stone breaking capability. For example, alarger tip on a smaller shaft would have more potential area of contacton a stone for better stone breaking capability while allowing forbetter shaft flexibility and/or irrigation capacity.

Different methods may be used to manufacture the guide features of thedistal tip of lithotripsy shaft 12. By way of example, one such methodis electrical discharge machining (EDM). This method would allow forprecise cutting from a blunt end of a lithotripsy shaft to formbeveling, tapering, sharp points, and/or protrusions.

Lithotripsy Shaft Driver

Lithotripsy shaft driver 17 may be controlled using various types ofdriving power, including pneumatic, ultrasonic, mechanical,electromechanical, electromagnetic, hydraulic, piezoelectric, or by acombination of different driving power. In the case of electromagneticdriving power, solenoids or coils, or the like may be used withinlithotripsy shaft driver 17 to control the movement of lithotripsy shaft12. In the case of ultrasonic driving power, the frequency of operationwould be greater than 20 kHz in order to reduce the discomfort fromexcessive audible noise. In the case of electromechanical or pneumaticdriving power (i.e. an “impact” driven lithotripsy shaft), the frequencyof operation would be typically less than 10-100 Hz. Pneumatic drivingpower may include the use of a CO₂ cartridge or a connection to an airsupply hose. One example embodiment of mechanical driving force includesuse of a spring-loaded cam shaft or mechanism to produce abrupt forwardmotion and a slower backward motion of the lithotripsy shaft to impartgreater impact on the physiologic calculus of interest. It iscontemplated that, in a preferred embodiment, lithotripsy shaft 12 willbe driven under ultrasonic power, potentially resulting in moreeffective stone destruction and shorter procedure duration.

Choice of driving power will affect the strength as well as thefrequency of impact, and will therefore affect the speed andeffectiveness of calculus disintegration. Smaller stones may requirehigher oscillation frequencies, while larger stones may require loweroscillation frequencies, for more efficient reduction of stone size. Itmay be possible to determine, in advance of the procedure, thecomposition or hardness of the calculi of interest by various imagingtechniques, including but not limited to ultrasound, X-ray, CT, or MRI,and thereby tailor the type of driving power to be the most effectivetechnique for a given calculus type. It may be possible to swap out thetype of driver during the lithotripsy procedure to more effectivelydisintegrate a challenging calculus.

FIG. 5 illustrates the distal end of a lithotripsy shaft 12 with guidefeatures with stone retrieval device extending therethrough at thedistal end an insertion device.

Controls

Controls may be provided for controlling movement of any one or more ofthe following: deflection of the active deflection section of theflexible shaft, extension and retraction of the stone retrieval device,the extension and retraction of the lithotripsy shaft from the distalend of the endoscope, and/or the driving of lithotripsy shaft to impactactive force upon a calculus of interest.

Control of deflection of the active deflection section of the flexibleshaft 27 may be accomplished through deflection control lever 19.Control wires built into flexible shaft 27 control deflection in a firstand second direction via control lever 19. Control lever 19 may beprovided with a lock position to restrict the distal end 13 of flexibleshaft 27 to an extended and essentially straight line position 11 a.Extended position 11 a allows for more effective stone breaking byfacilitating more of the energy from lithotripsy driver 17 impacting aphysiologic calculus of interest.

Control of extension and retraction of the stone retrieval device may beaccomplished through stone retrieval device handle 24 and thumb control23. Thumb control 23 may be in the form of a slider, trigger, thumbwheel, scissors-like handle grip, or other reasonable control mechanism.Thumb control 23 may act to move stone retrieval device into and out ofthe distal tip of lithotripsy shaft 12 and the distal tip of flexibleshaft 27. Movement of the stone retrieval device into the distal tip oflithotripsy shaft 12 causes stone retrieval device 14 to close and,similarly, movement of stone retrieval device out of the distal tip oflithotripsy shaft 12 and the distal tip of flexible shaft 27 causesstone retrieval device 14 to open. Stone retrieval device 14 can beextended and retracted from the distal tip 13 of flexible shaft 27 whiledistal tip 13 is either fully extended, fully retracted, or at anyposition there between.

Control of extension and retraction of the lithotripsy shaft 12 from thedistal end of the endoscope may be accomplished by different mechanisms.For example, in the illustrated embodiment, control of lithotripsy shaft12 is accomplished through a combination of translation stage 18 andslide lever control 20. Translation stage 18 allows for movement betweenone of two positions. A first position being a non-deployed position inwhich the distal end of lithotripsy shaft 12 is withdrawn such that itdoes not interfere with active deflection of the distal tip of flexibleendoscope into a deflected position such as position 11 b. A secondposition being a deployed position in which the lithotripsy shaft isextended beyond the distal tip of flexible shaft 27 by a distancesufficient enough to allow physiologic calculi to be impacted and brokendown. Slide lever control 20 may provide fine tuning of the position ofthe distal tip of lithotripsy shaft 12 toward or away from a targetlocation with more exact precision.

In one embodiment, a mechanism for advancing and controlling theposition of a laser fiber or other filamentous tool may be located inthe same position as lithotripsy driver 17, providing substantially morefine control over such filamentous tools than can be had by manualmanipulation. Translation stage 18 may be replaced alternateconfigurations in other embodiments, including use of a moving cylinderin a tube, for example.

Control of lithotripsy shaft driver 17 may be accomplished via buttonson the proximal end of the endoscope handle 29, through a separateconsole control, or via a footswitch, for example. Control oflithotripsy shaft driver 17 would function to turn active stone breakingon or off for one or more of the various types of driving techniquesdescribed above. Active stone breaking would preferably occur in thepresent invention when the flexible endoscope shaft was in asubstantially extended position, as in position 11 a, so as to minimizethe dissipation of energy around a bend.

The invention claimed is:
 1. An apparatus, comprising: an endoscopeincluding: a flexible shaft having an active deflection section at adistal tip, the flexible shaft defining a working channel extending froma proximal end to a distal end of the flexible shaft; a handle connectedto the proximal end of the flexible shaft; and a lithotripsy shaftconfigured to be inserted into the proximal end of the working channeland advance from the distal end of the working channel to break up astone at the distal end of the flexible shaft, wherein the lithotripsyshaft includes: a body portion, and a plurality of guide projectionsextending longitudinally from a distal end of the body portion, theplurality of guide projections defining a plurality of guide passagesbetween each guide projection of the plurality of guide projections, theplurality of guide projections and the plurality of guide passagesconfigured to facilitate passage of a stone removal device.
 2. Theapparatus of claim 1, wherein the stone removal device is configured tobe inserted into the proximal end of the working channel of the flexibleshaft for retrieval of a stone at a distal end of the flexible shaft byprotruding from the lithotripsy shaft.
 3. The apparatus of claim 1,wherein the plurality of guide protrusions include at least one selectedfrom a list including beveling, tapering, funnel-shaping, sharp tips,and pointed tips.
 4. The apparatus of claim 1, wherein the plurality ofguide protrusions include three protrusions extending from the distalend of the lithotripsy shaft.
 5. The apparatus of claim 1, wherein theplurality of guide protrusions include four protrusions extending fromthe distal end of the lithotripsy shaft.
 6. An apparatus, comprising: anendoscope including: a flexible shaft having an active deflectionsection at a distal tip, the flexible shaft defining a working channelextending from a proximal end to a distal end of the flexible shaft; ahandle connected to the proximal end of the flexible shaft oriented atan angle with respect to the longitudinal axis of the proximal end of astraight portion of the flexible shaft; a lithotripsy shaft configuredto be inserted into the proximal end of the working channel and advancefrom the distal end of the working channel to break up a stone at thedistal end of the flexible shaft, wherein the lithotripsy shaftincludes: a body portion, and one or more guide projections extendingfrom a distal end of the body portion; and a stone retrieval deviceconfigured to extend through the lithotripsy shaft for retrieval of astone at the distal end of the flexible shaft, wherein the one or moreguide projections facilitate passage of wires or filaments of the stoneretrieval device there through, and wherein the one or more guideprojection includes at least one selected from a list includingbeveling, tapering, sharp tips, and pointed tips configured to engagewith the stone.
 7. The apparatus of claim 6, wherein the stone retrievaldevice is a stone basket or a stone grasper.
 8. The apparatus of claim6, further including controls for controlling movement of any one ormore of deflection of the active deflection section of the flexibleshaft, extension and retraction of the stone retrieval device, theextension and retraction of the lithotripsy shaft from the distal end ofthe flexible shaft, or active stone breaking via driving of thelithotripsy shaft.
 9. A method, comprising: inserting a stone retrievaldevice into a proximal end of a lithotripsy shaft through a channel inthe lithotripsy shaft, wherein the lithotripsy shaft includes: a bodyportion, and a plurality of guide projections extending from a distalend of the body portion, the plurality of guide projections defining aplurality of guide passages between each guide projection of theplurality of guide projections; extending the stone retrieval devicefrom the lithotripsy shaft through the plurality of guide projections;capturing a stone with the stone retrieval device and bringing the stonesubstantially in line with the distal end of the lithotripsy shaft; anddriving the lithotripsy shaft under power toward the stone to break itup with force.
 10. The method of claim 9, wherein the stone retrievaldevice is a stone basket or stone grasper.
 11. The method of claim 9,wherein the plurality of guide projections are provided with a sharptip.
 12. The method of claim 9, further including a lithotripsy shaftdriver configured to drive the lithotripsy shaft under power, whereinthe lithotripsy shaft driver is driven pneumatically, ultrasonically,mechanically, electromechanically, electromagnetically, or by acombination of different driving power.